You can set up your system to perform automatic application rollout
for your high availability applications. The automatic application rollout
update process stops or pauses each application server that is hosting a cluster
member that needs updating.
Before you begin
Determine which application servers are hosting the cluster members
that need updating.
About this task
If you have a high availability application that frequently requires
updates, you might want to automatically control the rollout of these updates.
When setting up the rollout update process you must decide whether you
want the application servers to stop or pause while the update is made to
an application. If you want the servers to pause, you must configure the node
agent to allow the rollout update process to pause and resume the servers.
You do not have to make any configuration changes if you want the rollout
update process to stop and start the servers. However if the rollout update
process stops and starts the servers, the process takes much longer to complete.
When
an application server pauses, all requests already in the queue for that server
are allowed to complete, but no new requests are accepted. Both the sysplex
distributor and the WebSphere® Application Server web server plug-in
route work away from the server that is paused. After all of the requests
assigned to that server complete, the application update process starts on
that server.
When the update process is complete, the listener for
that server resumes and the sysplex distributor and the WebSphere Application
Server web server plug-in assign new work to that server. This process is
repeated for all of the other servers in the cluster until all of the affected
cluster members are updated.
To prepare your system to automatically
rollout updates to a high availability application:
Procedure
- Determine whether you want the rollout update process to stop or
pause the affected application servers.
- If you want the rollout update process to stop a server before it performs
an application update, go to step 5.
- If you want the rollout process to pause a server before it performs an
application update, go to step 2. Steps 2, 3, and 4 are configuration changes
that enable the rollout update process to pause and resume servers during
an application update. You only have to make these changes once.
- Add the com.ibm.websphere.zos.mvsservices.enable and com.ibm.websphere.zos.rollout.pauseresume custom
properties to the node agent settings in the master configuration repository
on the deployment manager server. These properties must be added
to the settings for all of the node agents on which you want to automatically
start the MVSServices MBean.
- In the administrative console, click node_agent_name >
Administration Services > Custom Properties > New
- Enter com.ibm.websphere.zos.mvsservices.enable in the
Name field, and true in the Value field.
- Click Ok .
- Click New .
- Enter com.ibm.websphere.zos.rollout.pauseresume in the
Name field, and true in the Value field.
- Click Ok .
- Repeat these steps for any other node agents on
which you want to automatically start the MVSServices MBean.
- Click Save to save your changes directly to the master configuration.
After you add the com.ibm.websphere.zos.rollout.pauseresume custom
property and set it to true, any future application rollouts on this
node are accomplished by pausing a listener for the application server, rather
than stopping that application server.
If the custom property com.ibm.websphere.zos.rollout.pauseresume
is set to true, but the MVSServices MBean is not running on the configured
node, the application servers on that node do not pause, and are not updated
during the application update process.
Messages are displayed on the MVS Console
when an application server is paused or resumed similar to the messages that
are displayed when an application server is stopped or started.
- Restart the node agent. When you restart the node agent,
the MVSServices MBean automatically starts.
- Update the application configuration repository in the master on
the deployment manager server.
Results
You are ready to start the rollout update process for an application
that you need to update.
What to do next
To start the rollout update process, in the administrative console,
click Applications > Enterprise Applications, select the application
to update, and click Rollout Update.
Avoid trouble: The
application you select must reside on at least one member of a cluster.
gotcha
This
function automatically stops or pauses the server, updates the application,
and then starts or resumes the server. Nodes are processed one at a time,
so only the server residing on the node being processed is affected, the servers
on the other nodes continue to process work. Eventually all of the nodes and
servers are updated.
The update process is complete when the updated
version of the application is running on all of the LPARs in the cluster.